#define  _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int a = 0;
	int b = 0;
	scanf("%d", &a);
	while (a>=3)
	{
		a=a /2;
		b = b + 1;
	}
	if (a <3)
	{
		printf("%d" ,b);
	}
}